The bobbin has been used for a long time to store a fiber, a wire or the like by winding the fiber, the wire, or the like around the bobbin. In addition to light objects such as fiber, heavy objects such as metallic wires may be wound around the bobbin. Accordingly, if the metallic wire is wound around the bobbin, the whole weight of the bobbin may be significantly increased.
The bobbin includes a cylindrical part, around which a wire is wound, and a flange that has a diameter greater than that of the cylindrical part to prevent the wound wire from getting out of both sides of the cylindrical part. In other words, the wire is wound around the cylindrical part, and prevented from getting out of the cylindrical part by the flange so that the wire can be maintained in a wound state. For example, four bobbins 10, around which wires for electric discharge machining are wound, are received in a box 1 divided by four partitions 2 as shown in FIGS. 1 and 2.
Actually, in the market, a plurality of bobbins, around which electric discharge machining wires are wound, are packed in a box to be sold. If bobbins, around which wires are wound, have light weights, a user can simply lift the box of the bobbins by using a hand. However, if heavy metallic wires such as wires for electric discharge machining are wound around the bobbins, each bobbin may have the weight of at least several tens kilograms. In this case, the user cannot easily lift each bobbin. In addition, the user may have a significant difficulty when lifting the bobbin by putting the hand between a box wall and each bobbin. Further, when the bobbin is taken out of the box in use, the bobbin may be frequently placed on a floor. In this case, since the bobbin has a cylindrical shape and a heavy weight, the bobbin may be rolled, causing injury to the foot of the user.